I would choose just two elements, 3 is really pushing it. On my ele, I'm really low on my SP and I can't level the skills I need when I can level them. And in the end, you'd be using only a few skills to kill your mobs, you won't have the time to use all 4. Sure, use it for Elemental Burn, but you can just use the first tier skills to fill it up.
Edit: Is this a guide or just a question?